Our overall objective continues to be the understanding of mechanism, structural foundation and regulation of basic biological processes involving movement at the subcellular level. Our analyses include: chromosome movement, mitotic spindle assembly and movement, cell division, fertilization, gametogenesis and cytoplasmic streaming which share in common the attribute of transient assembly and organization of anisotropic, tubulin and/or acto-myosin fibers. We approach this objective by developing and applying new optical, mechanical, photochemical, thermal, electro-optical, electro-mechanical and other methods which allow measurement of physical parameters directly in localized regions in functioning living cells. High resolution polarization microscopy, piezo-electrically operated micro-manipulation, microinjection, microirradiation and immuno-fluorescence staining are among the approaches we employ. Thermodynamic analyses and model building as well as studies of the basic physical principles underlying the measurements are an integral part of this effort.